Distributed Secondary Frequency and Voltage Control of Multiagent Based Autonomous Micro Grid with Enhanced Active and Reactive Power Sharing

Abstract

Primary frequency and voltage control of Micro grid (MG) generally adopt P-f and Q-U droop control to balance power supply and load demands, however, after reach a new power balance MG frequency and voltage would deviate from rated value, need secondary control to restore them. Centralized secondary frequency and voltage restoration in MG have high computation and communication reliability requirements for central PC. This paper presents multi agent based autonomous MG, secondary restoration function is realized in local agents in decentralized way, therefore increase MG operation reliability. Due to output and line impedance between distributed generations (DGs), DGs' terminal voltages are generally different so it's difficult for DGs to share active and reactive power. In the proposed MG, DGs could share power through dynamically changing its droop curve in local agents, thus power sharing capability for DGs are enhanced. Simulations results are provided to verify the feasibility of the proposed control strategy.